what is the height from the floor to the top of the arm rest when the chair is in the lowest position?
It is just about 29 inches. This height is with polyurethane wheels that did not come with the chair. These wheels seem to be slightly higher than the wheels it came with - about 1/2 inch taller.
How do you install the casters?
Place one castor stem into place at the end of one of the legs in the chair base. Turn the base right-side up on the floor. Using your hands, arms and body weight gently push down onto that leg until the castor "pops" into place and locks. Do each other castor the same way- one at a time.
Is the seat plastic or cloth?
The seat has like a mesh cloth covering and very comfortable.
Is It Waterproof?
The material is mesh and breathable so while I've never spilled anything on it I'd say it's probably water resistant
Does the chair itself lean back?
Yes, it does. Pull the lever you use to raise or lower the seat straight out to lean backwards. Put the seat upright and push the lever back in to lock it and stop it from leaning backwards.
width of seat?
It is 20" width and 20" depth.
what is the seat size in the back part of the seat?
what is the height seat adjustment, compressed air or mechanical
It must be compressed air. One touch raises or lowers it
Can the back be locked to stop from leaning?
The lever that lifts it up and down is also the lock. Pull out it leans back, push in it doesn't. There is a nozzle like thing on the bottom that you tighten and loose to make it lean more or less.
Does the thick side of the seat cushion go to the front or the back?
The thick part of the seat cushion goes from thick to front to just a bit thinner in the back VERY comfortable and I have it on carpet and moves around great as I see most people with other chairs have the thick plastic underneath to roll chair around I don’t need that..this chair works great on carpet alone!